It is well known that fluidised bed reactors have many applications but with particular bias towards exothermic chemical ractions which often require no supplementary thermal energy to be supplied to enable the reaction to proceed. Mildly endothermic reactions can also be carried out in a fluidised bed reactor and any supplementary thermal energy required has, in the past, generally been provided by fluidising the bed with preheated gases, which may be combustion gases, or by actually combusting material within the fluidised bed to generate such heat.
One alternative form of heating which has been proposed and implemented commercially in a process for producing hydrogen cyanide from methane and ammonia, is a fixed fluidised bed consisting of particles of coke or char. The heating is effected by passing an electrical current through the coke or char to generate, resistively, the required heat. It must be noted that in this process all the reactants and products are gaseous.
Other reactions that have been carried out in a resistance heated fluidised bed is the gasification of coal char using steam to produce carbon monoxide and hydrogen and the formation of ultra-microcrystallite silicon carbon on the surface of carbon particles fluidised together with silicon dioxide. In the former case the products are gaseous and in the latter, the solid product is recovered from the carbon particles in a batchwise manner.
It is the object of this invention to provide a method of carrying out chemical reactions in a fluidised bed reactor in which electrical resistance heating is employed but wherein a reactant, and optionally a reaction product, can be in the form of solid particles and can be added and removed in a continuous or semi-continuous manner.